The gunfire that put a Michigan hospital on lockdown and invoked fears of an active shooter was all because a man’s co-worker did not invite him to his father’s funeral, cops say.

Robert Paljusevic, 21, is facing charges of assault with intent to murder, felony firearm possession and carrying a concealed weapon for shooting his co-worker in the parking garage of Corewell Health Beaumont Troy Hospital in the Detroit area. Hospital staff alerted Troy police officers  shortly after 7 a.m. Thursday about an “active shooter.” Cops quickly determined that there was no active shooter, but rather an incident between two hospital employees. Security found the 25-year-old victim suffering from gunshot wounds to his arm. He was treated for his injuries at the hospital’s emergency department.

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Detectives say they later learned that the victim was driving into the parking garage when Paljusevic allegedly opened fire at least five times, striking the car and hitting the victim twice in the arm. The victim identified Paljusevic as the shooter and cops arrested him at his home in nearby Macomb County some two hours later.

A Troy police detective laid out the agency’s case against the defendant in front of a judge on Sunday morning, local news outlets reported. The two had been buddies but the friendship soured after the victim did not invite Paljusevic to his father’s family-only funeral. Family members of the victim allegedly described Paljusevic as “possessive” of the victim with a “short fuse.”

Paljusevic attended a public viewing of the victim’s father and, according to the victim’s mother, had some choice words when he walked up to the casket, cops said.